A new study from researchers at the UNC School of Medicine, published in September of this year through Neuron, examines how junk food rewires the brain’s memory hub and could lead to a higher risk of cognitive dysfunction. This new research also looks into the possibilities for early interventions that could prevent long-term memory loss that is associated with obesity.
Led by UNC School of Medicine’s Juan Song, PhD, and Taylor Landry, Ph.D., researchers found that a special group of brain cells in the hippocampus, called CCK interneurons, exhibited overly active behavior after eating a high-fat diet (HFD), which is caused by the impaired ability of the brain to receive glucose (commonly known as sugar). This overactivity of the CCK interneurons disrupts how the hippocampus processes memories, even after only a few days of consuming the high-fat diet. This high-fat diet resembles typical Western-style junk food that is rich in saturated fat, including cheeseburgers and fries. Researchers also discovered that a protein called PKM2, which controls how the brain cells use energy, plays a key role in this problem.
“We knew that diet and metabolism could affect brain health, but we didn’t expect to find such a specific and vulnerable group of brain cells, CCK interneurons in the hippocampus, that were directly disrupted by short-term high-fat diet exposure,” Song noted. “What surprised us most was how quickly these cells changed their activity in response to reduced glucose availability, and how this shift alone was enough to impair memory.”
The study was conducted using mouse models, which were placed on high-fat diets resembling fatty junk food before starting behavioral testing. Within four days of the high-fat diet being consumed, results showed that CCK interneurons in the brain’s memory hub became abnormally active. These results suggest that fatty junk foods can affect the brain and its ability to store memory almost immediately, well before the onset of weight gain or diabetes.
These research findings highlight how sensitive memory circuits are to diet, which underscores the importance of nutrition in maintaining a healthy brain. The study also indicates that a high-fat diet, rich in saturated fats, could potentially lead to an elevated risk of developing neurodegenerative diseases, such as dementia and Alzheimer’s.
The study also showed that restoring brain glucose levels actually calmed down the overactive neurons, fixing the memory problems in the mice. Research showed that interventions like dietary modifications or pharmacological approaches may be effective in preserving brain health for obesity-related neurodegeneration. Interestingly, researchers also discovered that dietary interventions like intermittent fasting periods following a consumption of the high-fat diet were sufficient to normalize CCK interneurons and improve memory function.
Research is ongoing to further understand how these glucose-sensitive neurons disrupt brain rhythms that support memory, with researchers planning to test whether these therapies could be translated into humans and how a high-fat diet could be a factor in Alzheimer’s disease. There are also plans to explore how lifestyle-based interventions, such as dietary patterns, could stabilize brain glucose and see if they offer protective benefits.
